Urgent 'solar storm' warning as giant sunspot threatens mass power cuts

The sunspot stretches for 124,000 miles (Image: Getty)

An urgent "solar storm" warning has been issued by the U.S. government - with Americans warned of major power outages in a matter of hours.

The giant sunspot named AR3664, which is 124,000 miles-wide according to Spaceweather.com, has released intense bursts of energy and radiation towards planet Earth.

The X-class solar flares, which are the most powerful of its kind, could knock out communications, the electric power grid, and navigation.

America's official Space Weather Prediction Center (SWPC) say they are monitoring the sun following the series of flares and coronal mass ejections (CMEs) that began at 5am on Wednesday.

They report: "Space weather forecasters have issued a Severe (G4) Geomagnetic Storm Watch for the evening of Friday, May 10. Additional solar eruptions could cause geomagnetic storm conditions to persist through the weekend."

In a statement Thursday (9 May), SWPC warned: "Geomagnetic storms can impact infrastructure in near-Earth orbit and on Earth's surface, potentially disrupting communications, the electric power grid, navigation, radio and satellite operations.

"SWPC has notified the operators of these systems so they can take protective action."

However, SWPC add there is a benefit to geomagnetic storms in that they can also trigger spectacular displays of aurora on Earth.

They say: A severe geomagnetic storm includes the potential for aurora to be seen as far south as Alabama and Northern California."